Scientists at the University of California, Riverside have shown that certain mosquito nerve cells, known as cpA neurons, cause mosquitoes to be attracted to humans by detecting exhaled carbon dioxide (CO2) and odors emitted from human skin. Their findings, published Dec. 5 in the journal Cell, may have implications for the control of mosquitoes and the diseases they transmit. The study was supported by the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health.
By studying Aedes aegypti and Anopheles gambiae mosquitoes, which are key transmitters of dengue and malaria, respectively, the researchers showed that cpA neurons are sensitive detectors of human odors, which in their experiments stimulated mosquitoes to move toward glass beads coated with human foot odor. When the cpA neurons were chemically inactivated, this attraction was reduced.
In follow-up experiments, the researchers screened more than 440,000 chemicals for those with structures that can interact with the specific proteins on the surface of cpA neurons that detect human odors and CO2. Of thousands with such a structure, they tested 138 and found several that had previously been recognized as safe for human use and were pleasant-smelling, inexpensive and present in the natural environment. They pursued two compounds for additional study: ethyl pyruvate, a fruity-scented compound that neutralized cpA neurons' ability to detect and reduced attraction to human foot odor; and cyclopentanone, a minty-smelling compound that activated the cpA neurons similarly to CO2 and attracted mosquitoes to a trap. With further study, the authors write, compounds such as these may be developed into two complementary mosquito control approaches: masking insects' attraction to humans, and luring them away from humans or toward a trap.
GM Tauxe et al. Targeting a dual detector of skin and CO2 to modify mosquito host seeking. Cell DOI: 10.1016/j.cell.2013.11.013 (2013).
Adriana Costero-Saint Denis, Ph.D., vector biology program officer in NIAID's Parasitology and International Programs Branch, is available to discuss the findings.
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